JPH05142107A - Dispensing device - Google Patents

Abstract

PURPOSE:To achieve a highly accurate metering and a small amount of control easily and at the same time to enable a device to be compact, light, and inexpensive. CONSTITUTION:A title item is provided with a liquid container 2 which houses a liquid W and has a delivery port with a size which does not cause the internal liquid W to be delivered while no dispensing voltage is applied to and one electrode part which does not contact the liquid W within the liquid container 2 electrically, preferably a positive side electrode part 3. Furthermore. the other electrode part which is placed at the front in the direction of delivery of a delivery port 2c, preferably a negative side electrode part 7, a DC power supply part 5, and a control part 6 which controls power supply from the DC power supply part 5 for the electrode parts 3 and 7 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispensing apparatus suitable for spotting a trace amount of liquid, which is suitable for a biochemical analysis system or the like.

[0002]

In the field of biochemical analysis, generally 1 μm
In order to handle a small amount of liquid of about 1 liter, a dispensing device for spotting with high precision is used.

A conventional dispensing device 50 is shown in FIG. In the figure, reference numeral 51 is an intake / exhaust cylinder, which has a piston 52 slidable in the axial direction inside thereof, and a piston rod 53 connected to the piston 52 is an intake / exhaust cylinder 5.
1 to the outside from the rear end. In addition, the intake and exhaust cylinder 5
A suction port 54 is provided at the front end of 1, and a liquid container (pipette) 55 for storing a liquid is provided in the suction port 54. on the other hand,
A threaded portion 56 is formed on the piston rod 53 protruding to the outside and is screwed into a nut 57.
The ball screw mechanism 58 is configured. Further, a driven gear 59 is formed on the outer periphery of the nut 57 and meshes with a drive gear 61 provided on the output shaft of a rotary drive unit 60 having a servo motor, a speed reduction mechanism and the like built therein. Then, the rotation driving unit 60 is connected to the control unit 62.

Therefore, by reversely operating the rotary drive unit 60 in advance, the piston rod 53 is retracted, and the liquid such as the test liquid and the reaction liquid is sucked and contained in the liquid container 55. The rotation drive unit 60 is normally operated,
At the same time, the control unit 62 detects the rotation speed and the like by the rotation speed sensor incorporated in the rotation driving unit 60, and controls the forward movement position of the piston rod 53 based on the rotation speed sensor, so that the preset liquid amount is adjusted to the liquid container 55. Weigh from and discharge (spotting)
it can.

[0005]

However, the conventional dispensing device 50 has the following problems.

First, since a mechanical error due to backlash in a mechanical transmission mechanism such as a reduction mechanism and a ball screw mechanism becomes large, it is difficult to perform high-accuracy weighing and minute control.

Secondly, since a mechanical rotary drive unit and a transmission mechanism are used, the structure is complicated and the cost is increased, and the weight of the entire apparatus cannot be reduced.

The present invention solves the problems existing in the prior art as described above, and it is possible to easily perform high-accuracy weighing and minute control, and to reduce the size, weight and cost of the device. The purpose is to provide a dispensing device capable of

[0009]

Dispensing device 1 according to the present invention
Is a discharge port 2 of a size that does not discharge the internal liquid W in a state in which the liquid W is contained and a dispensing voltage is not applied.
a liquid container 2 having c, and one electrode portion electrically contacting the liquid W in the liquid container 2, preferably the positive electrode portion 3
And the other electrode portion arranged in front of the discharge port 2c in the discharge direction,
Desirably, it is provided with a negative electrode section 7, a DC power supply section 5, and a control section 6 for controlling power supply from the DC power supply section 5 to each of the electrode sections 3, 7.

In this case, between the positive electrode portion 3 and the negative electrode portion 7, a suction electrode portion 4p disposed near the discharge port 2c for sucking the liquid W from the discharge port 2c, and a suction electrode portion 4p. A concentrated electrode section 4q is provided in front of the discharge direction to concentrate the discharged liquid Wo. A positive voltage is applied to the suction electrode section 4p and the concentrated electrode section 4q, and the suction electrode section 4q is applied.
It is desirable that a voltage lower than that of the positive electrode portion 3 is applied to p, and a voltage higher than that of the suction electrode portion 4p is applied to the concentrated electrode portion 4q.

[0011]

According to the dispensing apparatus 1 of the present invention, the liquid Wo to be spotted is discharged from the liquid container 2 by the principle of the electrostatic spraying method. That is, in the state where the voltage for dispensing is not applied between the positive electrode portion 3 and the negative electrode portion 7, the liquid W is not discharged from the liquid container 2 by selecting the size of the discharge port 2c, but the control unit 6 is controlled. By applying a DC voltage from the DC power supply unit 5 between the positive electrode unit 3 and the negative electrode unit 7, the charged liquid W is sucked to the negative electrode unit 7 side and passes through the discharge port 2c. It is discharged to the outside. Further, if the suction electrode portion 4p and the concentrated electrode portion 4q are provided between the positive electrode portion 3 and the negative electrode portion 7, the suction electrode portion 4p can suck the liquid W from the discharge port 2c and the discharged liquid. Wo is the concentrated electrode section 4q
After being concentrated by, it reaches the negative electrode portion 7.

In this case, since the liquid W is discharged only while the voltage is applied between the positive electrode portion 3 and the negative electrode portion 7 or between the positive electrode portion 3 and the suction electrode portion 4p, the voltage If the application time is changed by the control unit 6, the amount of liquid discharged (spotted) can be controlled, that is, quantified.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the structure of the dispensing apparatus 1 according to the present invention will be described with reference to FIG.

In the dispensing apparatus 1, 2 is a liquid container for containing a liquid W such as a test solution or a reaction solution to be dispensed. The lower part is formed to have a gradually smaller diameter toward the lower side, and a discharge port 2c is provided at the center of the lower end. .. The discharge port 2c is a fine hole, and the size is selected so that the internal liquid W is not discharged in the state in which the dispensing voltage is not applied. The liquid container 2 is made of an insulating material.

Further, the positive electrode portion 3 formed in, for example, a rod shape is housed inside the liquid container 2 and is brought into electrical contact with the liquid W in the liquid container 2. On the other hand, a ring-shaped suction electrode portion 4p is arranged in the vicinity of the discharge port 2c located in front (lower side) of the discharge port 2c in the discharge direction, and a ring-shaped concentrated electrode is arranged in front (lower side) of the suction electrode part 4p. Part 4q is arranged. Further, a negative electrode portion 7 formed of a flat plate is arranged in front of (below) the concentrated electrode portion 4q, and a slide for spotting the discharged liquid Wo is placed on the negative electrode portion 7. (Target) Y is arranged.

On the other hand, 5 is a DC power supply unit capable of extracting a plurality of voltages of different sizes, and the maximum voltage (5
The first output section 5f that outputs a voltage of about kilovolts is connected to the positive electrode section 3 via the current detection section 11. The current detection unit 11 can use an ammeter or a non-contact current transformer, and the detected current detection value is given to the control unit 12.
In addition, the second output unit 5 that outputs a voltage lower than the maximum voltage
s is connected to the concentrated electrode section 4q via the second switch 14, and the third output section 5t that outputs a voltage lower than that of the second output section 5s is connected to the suction electrode section 4p via the third switch 15. . Further, the negative side of the DC power supply section 5 is connected to the negative side electrode section 7 via the first switch 13. Each switch 13, 14, 15 uses, for example, a switching transistor or the like, and the opening and closing (on-off) thereof is performed by the control unit 1.
Controlled by 2. The switches 13, 14, 15 and the control unit 12 form the control unit 6.

Next, the operation and usage of the dispensing device 1 according to the present invention will be described with reference to FIGS. 1 and 2.

First, the liquid container 2 contains the liquid W to be dispensed in advance. In this case, if the control unit 12 controls all of the switches 13, 14, and 15 to the open (OFF) side, no voltage is applied to the positive electrode portion 3, and thus the liquid W
Is not discharged from the liquid container 2.

On the other hand, if the control unit 12 controls the switch 13 to the closed (ON) side, the maximum voltage is applied between the positive electrode portion 3 and the negative electrode portion 7, and the liquid W is charged.
However, in the case of the embodiment, the positive electrode portion 3 and the negative electrode portion 7 are
The liquid W is not discharged from the liquid container 2 because the distance between them is set large and the suction electrode portion 4p and the concentrated electrode portion 4q are arranged between them. Next, the control unit 12 controls the switches 14 and 15 to the close (ON) side, and the voltages are applied to the suction electrode section 4p and the concentrated electrode section 4q from the third output section 5t and the second output section 5s, respectively. The charged liquid W is sucked by the suction electrode portion 4p and discharged to the outside through the discharge port 2c. In this case, the liquid Wo is discharged only during the period S (FIG. 2 (A)) in which the switch 15 is on (FIG. 2 (B)). Further, the discharged liquid Wo is concentrated in the concentrated electrode section 4
It is concentrated by q and spotted on the slide Y.

At this time, the current detection value Id (FIG. 2C) detected by the current detection unit 11 is the control unit 12
The flow rate of the liquid Wo that is applied to and discharged is calculated.
That is, in this case, the amount of the liquid Wo discharged is obtained by integrating the detected current value Id. Further, depending on the magnitude of the potential between the positive electrode part 3 and the suction electrode part 4p, the liquid W
The discharge state of o can be changed. For example, when the electric potential is low, the discharged state of the liquid Wo is in the form of water droplets and drops intermittently, but as the electric potential is increased, a continuous water flow is formed, and by increasing the electric potential, it can be atomized. In particular, the control accuracy of the liquid Wo is highest when the electrostatic atomization phenomenon that causes atomization is used. Further, the form of voltage application to the suction electrode portion 4p and the concentrated electrode portion 4q can be set arbitrarily. For example, the voltage may be temporally changed in a sawtooth shape, or each of the electrode portions 4p, 4q may be changed.
The application timing of the voltage with respect to may be different.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment.
For example, the electrode part interposed between the positive electrode part and the negative electrode part may be omitted, or one or three or more may be provided.
In addition, the detailed configuration, shape, material and the like can be arbitrarily changed without departing from the scope of the present invention.

[0023]

As described above, the dispensing device according to the present invention is
A liquid container having a discharge port of a size that does not discharge the internal liquid when a liquid is contained and a dispensing voltage is not applied, one electrode part that is in electrical contact with the liquid in the liquid container, and Since the other electrode portion arranged in front of the outlet in the discharge direction, the DC power supply portion, and the control portion for controlling power supply from the DC power supply portion to each electrode portion are provided, the following remarkable effects are achieved.

Since a mechanical error due to a mechanical transmission mechanism such as a speed reduction mechanism and a ball screw mechanism is eliminated, highly accurate weighing and minute control can be easily realized.

Since a mechanical rotary drive unit and a transmission mechanism are not required, the configuration can be simplified, the cost can be reduced, and the weight of the entire device can be reduced.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of a dispensing device according to the present invention,

FIG. 2 is a waveform diagram of signals and the like at the time of spotting by the dispensing device,

FIG. 3 is a configuration diagram of a main part of a dispensing device according to a conventional technique,

[Explanation of symbols]

 1 Dispensing device 2 Liquid container 2c Discharge port 3 Positive electrode part 4p Suction electrode part 4q Concentrated electrode part 5 DC power supply part 6 Control part 7 Negative side electrode part W Liquid Wo Discharged liquid

Claims (5)

[Claims] 1. A liquid container having a discharge port having a size for containing the liquid and not discharging the internal liquid when a dispensing voltage is not applied, and one of the liquid container electrically contacting the liquid in the liquid container. An electrode part, the other electrode part arranged in the discharge direction forward of the discharge port, a DC power supply part, and a control part for controlling power supply from the DC power supply part to each of the electrode parts. Note device. 2. The dispensing device according to claim 1, wherein one electrode portion is a positive electrode portion and the other electrode portion is a negative electrode portion. 3. A suction electrode part disposed between the positive electrode part and the negative electrode part in the vicinity of the discharge port to suck liquid from the discharge port,
The dispensing device according to claim 2, further comprising: a concentrated electrode unit arranged in front of the suction electrode unit in the discharge direction to concentrate the discharged liquid. 4. The suction electrode section applies a positive side voltage lower than the voltage of the positive side electrode section.
Dispensing device as described. 5. The concentrated electrode unit applies a positive voltage higher than the voltage of the suction electrode unit.
Dispensing device as described.